Actuator for high-pressure valve

Abstract

Provided is an actuator including a ball-type thrust amplifier therein that controls a valve in which a high-pressure fluid flows, and having less wear between members and a long lifespan. This actuator for a valve includes a thrust amplification mechanism therein, in which the thrust amplification mechanism includes a disk, a ball presser, a stem, and a plurality of balls that are sandwiched by and in contact with an upper surface of the disk, a tapered surface of the ball presser, and a tapered surface of the stem and disposed to move outward as the stem moves downward, the surfaces of the parts constituting the thrust amplification mechanism are coated with grease containing an additive, and the additive of the grease includes at least chloroalkane.

1 . An actuator for a valve comprising:
 a thrust amplification mechanism therein that increases thrust for pressing a valve body to open and close a flow path, wherein   the thrust amplification mechanism includes a disk provided between an output end of the actuator and the valve body and configured to transmit the thrust for pressing the valve body, a ball presser disposed above the disk and having a conical tapered surface spreading outward and downward, a stem configured to pass through a through hole formed in a central portion of the ball presser and having a tapered surface whose tip end on the valve body side is tapered, and a plurality of balls sandwiched by and in contact with an upper surface of the disk, a tapered surface of the ball presser, and a tapered surface of the stem and disposed to move outward as the stem moves downward,   a movement space of the balls is filled with grease containing an additive, and   the additive includes at least chloroalkane in a group of sulfurized spam oil, sulfurized aliphatic ester, dibenzyl disulfide, alkyl polysulfide, olefin polysulfide, xanthic sulfide, chlorinated paraffin, methyl trichloro stearate, the chloroalkane, lead naphthenate, alkylthiophosphate amine, and chloroalkylxanthate.   
     
     
         2 . The actuator for a valve according to  claim 1 , wherein
 the ball presser includes a contact member contacting with the balls, and a lid member configured to detachably press and fix the contact member from above.   
     
     
         3 . The actuator for a valve according to  claim 1 , wherein
 the actuator is of a type that generates thrust by a piston driven by air, and an upper end of the stem is detachably engaged with a lower portion of the piston.   
     
     
         4 . The actuator for a valve according to  claim 2 , wherein
 the actuator is of a type that generates thrust by a piston driven by air, and an upper end of the stem is detachably engaged with a lower portion of the piston.